U.S. patent application number 15/309205 was filed with the patent office on 2017-03-23 for turbocharger with a waste gate valve.
This patent application is currently assigned to PIERBURG GMBH. The applicant listed for this patent is PIERBURG GMBH. Invention is credited to MICHAEL-THOMAS BENRA, SVEN NIGRIN, MARTIN NOWAK, STEPHAN ZIELBERG.
Application Number | 20170082016 15/309205 |
Document ID | / |
Family ID | 52574149 |
Filed Date | 2017-03-23 |
United States Patent
Application |
20170082016 |
Kind Code |
A1 |
NOWAK; MARTIN ; et
al. |
March 23, 2017 |
TURBOCHARGER WITH A WASTE GATE VALVE
Abstract
A turbocharger includes a waste gate valve, a compressor with a
turbine, a turbine housing which houses the turbine, a bypass
channel with an opening cross-section, a bypass channel portion
formed in the turbine housing, an actuator housing with a separate
coolant channel, an electric motor arranged in the actuator
housing, a transmission with an output shaft, the transmission
being arranged in the actuator housing and being provided as a worm
wheel gear unit, and a control body coupled to the output shaft of
the transmission. The bypass channel bypasses the turbine. The
actuator housing is removably secured to the turbine housing. The
control body controls the opening cross-section of the bypass
channel.
Inventors: |
NOWAK; MARTIN; (LEVERKUSEN,
DE) ; BENRA; MICHAEL-THOMAS; (CASTROP-RAUXEL, DE)
; NIGRIN; SVEN; (DUESSELDORF, DE) ; ZIELBERG;
STEPHAN; (BOCHUM, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PIERBURG GMBH |
NEUSS |
|
DE |
|
|
Assignee: |
PIERBURG GMBH
NEUSS
DE
|
Family ID: |
52574149 |
Appl. No.: |
15/309205 |
Filed: |
February 19, 2015 |
PCT Filed: |
February 19, 2015 |
PCT NO: |
PCT/EP2015/053499 |
371 Date: |
November 7, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02T 10/12 20130101;
Y02T 10/144 20130101; F05D 2220/40 20130101; F02B 37/186 20130101;
F01D 5/04 20130101; F02B 39/005 20130101; F01D 25/24 20130101; F02B
33/40 20130101; F04D 25/045 20130101 |
International
Class: |
F02B 37/18 20060101
F02B037/18; F02B 39/00 20060101 F02B039/00; F01D 5/04 20060101
F01D005/04; F01D 25/24 20060101 F01D025/24; F02B 33/40 20060101
F02B033/40; F04D 25/04 20060101 F04D025/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 9, 2014 |
DE |
10 2014 106 515.8 |
Claims
1-12. (canceled)
13: A turbocharger comprising: a waste gate valve; a compressor
comprising a turbine; a turbine housing configured to house the
turbine; a bypass channel comprising an opening cross-section, the
bypass channel being configured to bypass the turbine; a bypass
channel portion formed in the turbine housing; an actuator housing
comprising a separate coolant channel, the actuator housing being
removably secured to the turbine housing; an electric motor
arranged in the actuator housing; a transmission comprising an
output shaft, the transmission being arranged in the actuator
housing and being provided as a worm wheel gear unit; and a control
body coupled to the output shaft of the transmission, the control
body being configured to control the opening cross-section of the
bypass channel.
14: The turbocharger as recited in claim 13, wherein the electric
motor comprises an input shaft which comprises a center axis which
extends substantially vertically with respect to the output shaft
of the transmission.
15: The turbocharger as recited in claim 14, further comprising: a
first coolant channel section configured to circumferentially
surround the transmission; and an actuator cover configured to
axially close the first coolant channel section.
16: The turbocharger as recited in claim 15, further comprising: a
second coolant channel section configured to radially enclose the
electric motor at least in part over an entire axial height; and a
motor cover configured to close the second coolant channel
section.
17: The turbocharger as recited in claim 16, further comprising two
passage openings configured to connect the first coolant channel
section and the second coolant channel section with each other.
18: The turbocharger as recited in claim 17, further comprising a
first partition wall formed in the first coolant channel section
between the two passage openings to the second coolant channel
section.
19: The turbocharger as recited in claim 18, wherein, the electric
motor comprises a receiving portion, and further comprising a
coolant inlet port and a coolant outlet port formed on the actuator
housing in the receiving portion of the electric motor.
20: The turbocharger as recited in claim 19, further comprising a
second partition wall arranged in the second coolant channel
section between the coolant inlet port and the coolant outlet port,
the partition wall being configured to extend in an axial direction
of the input shaft of the electric motor.
21: The turbocharger as recited in claim 15, wherein the waste gate
valve comprises electronic components which are arranged on the
actuator cover.
22: The turbocharger as recited in claim 21, further comprising: a
magnet connected with the output shaft of the transmission,
wherein, the electric components include a connector and a
contactless sensor which are configured to provide a position
feedback, the sensor being configured to communicate with the
magnet.
23: The turbocharger as recited in claim 15, further comprising
terminals for the electric motor formed on the actuator cover.
Description
CROSS REFERENCE TO PRIOR APPLICATIONS
[0001] This application is a U.S. National Phase application under
35 U.S.C. .sctn.371 of International Application No.
PCT/EP2015/053499, filed on Feb. 19, 2015 and which claims benefit
to German Patent Application No. 10 2014 106 515.8, filed on May 9,
2014. The International Application was published in German on Nov.
12, 2015 as WO 2015/169461 A1 under PCT Article 21(2).
FIELD
[0002] The present invention relates to a turbocharger with a waste
gate valve, a compressor, a turbine, a turbine housing, a bypass
channel for bypassing the turbine, a bypass channel portion which
is formed in the turbine housing, an actuator housing, an electric
motor which is arranged in the actuator housing, a transmission
which is arranged in the actuator housing, an output shaft of the
transmission, and a regulating element which is coupled to the
output shaft and controls an opening cross-section of the bypass
channel.
BACKGROUND
[0003] Turbochargers with waste gate valves have previously been
described. A turbocharger serves to increase the boost pressure and
thus to increase the power of the internal combustion engine. The
pressure which can be generated is always a function of the exhaust
gas quantity conveyed due to the turbine wheel being coupled with
the compressor wheel. It is therefore necessary to reduce or
control the drive power acting on the compressor under certain
operating conditions.
[0004] Waste gate valves are used therefor, among others, which
valves are arranged in a bypass channel via which the turbine can
be bypassed so that the turbine wheel is no longer acted upon by
the entire flow quantity of the exhaust gas. These waste gate
valves are most often designed as flap valves operated by a
pneumatic actuator which drives a linkage coupled with the
flap.
[0005] Since a high thermal load exists in the region of the
turbine housing due to hot exhaust gases, these pneumatic actuators
have been arranged in the region of the compressor, and in
particular at a distance from the turbine housing, in order to
reduce thermal load.
[0006] An exact control of the exhaust gas quantity discharged via
the bypass channel is, however, difficult to achieve with a
pneumatic actuator. Electric motors have therefore seen widespread
use as drives for waste gate valves in recent years. These were
typically also arranged at a distance from the turbine housing to
reduce thermal load so that linkages were still used for coupling
with the flap.
[0007] Because of ever decreasing available installation space, it
is desirable to arrange the actuators of the waste gate valves in
the immediate proximity to the valve itself since the installation
space necessary is thus reduced and a more precise control becomes
possible. When linkages are used, an increased wear of the
mechanical components, in particular due to increased transverse
forces in the region of the flap bearings, as well as increased
assembly efforts, often also occur.
[0008] WO 2012/089459 A1 therefore describes a turbocharger with a
water-cooled turbine housing and an integrated electric waste gate
valve. The housing in which the electric motor for driving the
waste gate valve and the transmission are arranged is a part of the
turbine housing in which corresponding cooling channels are formed
to carry water. The electric motor and the transmission are thus
mounted on the turbine housing, wherein the necessary opening in
the turbine housing is closed with a cover. The bearing of the
valve is also arranged in the turbine housing.
[0009] The use of the above waste gate valve arrangement still
risks a thermal overload of the actuator since the cooling medium
is strongly heated while flowing through the turbine housing and is
therefore not immediately effective at the actuator. The actuator
is also subjected to a direct thermal radiation from outside so
that, under unfavorable conditions, a risk of overheating still
exists.
[0010] The arrangement of the electric motor directly in the
turbine housing generally leads to thermal overload. A relatively
large installation space is also required in the axial direction of
the output shaft despite the integration of the actuator into the
turbine housing.
SUMMARY
[0011] An aspect of the present invention is to provide a
turbocharger having a waste gate valve which reliably avoids a
thermal overload of the actuator drive. Another aspect of the
present invention is that the waste gate valve is easy to assemble,
requires an installation space which is as small as possible, and
has the greatest possible controllability exactness.
[0012] In an embodiment, the present invention provides a
turbocharger which comprises a waste gate valve, a compressor
comprising a turbine, a turbine housing configured to house the
turbine, a bypass channel comprising an opening cross-section, a
bypass channel portion formed in the turbine housing, an actuator
housing comprising a separate coolant channel, an electric motor
arranged in the actuator housing, a transmission comprising an
output shaft, the transmission being arranged in the actuator
housing and being provided as a worm wheel gear unit, and a control
body coupled to the output shaft of the transmission. The bypass
channel is configured to bypass the turbine. The actuator housing
is removably secured to the turbine housing. The control body is
configured to control the opening cross-section of the bypass
channel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present invention is described in greater detail below
on the basis of embodiments and of the drawings in which:
[0014] FIG. 1 is a side view of a turbocharger of the present
invention with a waste gate valve in perspective view;
[0015] FIG. 2 is an exploded perspective side view of an actuator
housing of the waste gate valve in FIG. 1; and
[0016] FIG. 3 is a sectional side view of the actuator housing of
the waste gate valve in FIG. 1.
DETAILED DESCRIPTION
[0017] Due to the fact that the actuator housing is detachably
fastened on the turbine housing and has a separate coolant channel,
with the transmission being a worm wheel gear unit, a separated
coolant supply to the actuator is provided so that the supply can
be effected in depending on the temperature actually prevailing in
the actuator housing and independent of the temperature in the
turbine housing. The effect of the heat radiation from the turbine
is significantly reduced since the actuator housing is cooled
directly. A thermal separation from the turbine housing is achieved
that significantly reduces the heat transfer into the actuator
housing. The advantage of a direct flap drive nevertheless exists
by which a very precise control of the waste gate valve becomes
possible. Manufacture and assembly of the actuator is simple even
though the coolant channel is formed in the actuator housing since
only a few components must be used. The installation space used in
the axial direction of the output shaft is significantly reduced.
The electric motor may thus be arranged at a certain distance from
the turbine housing and under a lower resulting thermal load
without increasing the axial height of the installation space.
[0018] In an embodiment of the present invention, the center axis
of the input shaft of the electric motor can, for example, extend
substantially vertically with respect to the output shaft so that a
minimal structural height is obtained in the direction of the
output shaft. Good accessibility of the actuator and its components
is additionally provided even in the mounted state.
[0019] In an embodiment of the present invention, a first coolant
channel section can, for example, circumferentially surround the
transmission and be closed axially with an actuator cover. Great
amounts of heat may thus be dissipated from the actuator. The
bearing region of the output shaft is well cooled so that the
service life of the bearings is extended. An introduction of heat
from outside by thermal radiation is also reliably prevented.
[0020] To achieve a particularly good cooling of the thermally
sensitive electric motor and, correspondingly, to dissipate
sufficient heat, a second coolant channel section encloses the
electric motor radially, at least in part, over the entire axial
height and is closed with a motor cover. The heat from the electric
motor can thus be guided to the outside and a thermal separation is
provided from the possibly hot surroundings of the actuator.
Thermal overload can thus be reliably avoided. The coolant channel
can be formed in a die-casting process using a slide gate so that
no lost cores must be used. Manufacturing costs are thereby
reduced.
[0021] In an embodiment of the present invention, the first coolant
channel section and the second coolant channel section can, for
example, be connected with each other via two passage openings.
Both coolant channels sections have a common through-flow so that
additional conduits may be omitted. Assembly is thereby simplified
and the installation space used is reduced.
[0022] In an embodiment of the present invention, a partition wall
is advantageously formed in the first coolant channel section which
is arranged between the two passage openings to the second coolant
channel section. A forced flow around the transmission and thus
around the bearing of the output shaft is obtained thereby.
[0023] In an embodiment of the present invention, a coolant inlet
port and a coolant outlet port can, for example, be formed on the
actuator housing in a receiving portion of the electric motor. An
independent cooling circuit for the waste gate actuator can be
connected via these ports so that an exact temperature control is
possible.
[0024] In an embodiment of the present invention, a partition wall
can, for example, be arranged in the second coolant channel section
between the coolant inlet port and the coolant outlet port, the
partition wall extending in the axial direction of the input shaft
of the electric motor. A short circuit flow from the inlet port to
the outlet port is thereby prevented. A forced flow around the
entire transmission and the electric motor, and thus a cooling over
the entire circumference, is instead provided.
[0025] In an embodiment of the present invention, electronic
components of the waste gate valve can, for example, be arranged on
the actuator cover so that additional components to be mounted
which receive the electronics can be omitted. This additionally
facilitates assembly.
[0026] In an embodiment of the present invention, a connector and a
contactless sensor for position feedback can, for example, be
fastened on the actuator cover, the sensor communicating with a
magnet connected with the output shaft. An otherwise necessary
sealing of a connector passage is thereby omitted. The actuator
cover can be formed integrally with the necessary lines by an
injection molding. Assembly steps are thus omitted that would
otherwise be necessary for assembling the electronics into the
housing. The magnet is fastened either directly on the output shaft
or indirectly on a component connected for rotation with the output
shaft, such as the output gear. A position detection is thus
performed at the output shaft itself so that errors caused by
inaccuracies at the transmission are excluded.
[0027] Further simplification is achieved if the terminals for the
electric motor are formed on the actuator cover so that an electric
contacting of the electric motor is effected automatically when
affixing the cover. All live lines can thus be formed on the cover
or be molded therein. A simplification of the assembly and the
manufacture of the actuator is thereby achieved.
[0028] The output shaft is connected with a flap shaft, in
particular via an Oldham coupling, a control body being fastened to
the flap shaft, whereby a good controllability with a simultaneous
thermal separation or isolation is achieved in order to reduce the
heat transported into the actuator via the shaft. This coupling
also can be made from a material with poor thermal conductivity,
such as ceramics. This coupling also serves as a tolerance
compensation element between the flap shaft and the output
shaft.
[0029] A turbocharger with a waste gate valve is accordingly
provided that is reliably protected from thermal overload and which
may be mounted to the turbocharger as a preassembled component so
that assembly is facilitated, while making a very precise control
of the waste gate valve possible. The cooling can be separately
adapted to the requirements of the turbine and the valve. The
necessary installation space is significantly reduced compared to
known designs.
[0030] An embodiment of a turbocharger of the present invention
with a waste gate valve is illustrated in the drawings and will be
described hereunder.
[0031] The turbocharger 10 illustrated in FIG. 1 comprises a
compressor 12 with a compressor wheel arranged in a compressor
housing 14, and a turbine 16 with a turbine wheel arranged in a
turbine housing 18. The turbine wheel is fastened in a manner known
per se on a common shaft with the compressor wheel so that the
movement of the turbine wheel caused by an exhaust gas flow in the
turbine housing 18 is transmitted to the compressor wheel via the
shaft, whereby an airflow is compressed in the compressor housing
14.
[0032] A bypass channel 22 in which a waste gate valve 15 is
arranged branches off upstream of the spiral channel 20 surrounding
the turbine wheel in the turbine housing 18. This bypass channel 22
opens into the subsequent exhaust gas channel of the internal
combustion engine behind the spiral channel 20.
[0033] A valve seat 24 of the waste gate valve 15 that surrounds an
opening cross section of the bypass channel 22 is situated in a
bypass channel section 23 formed in the turbine housing 18. The
opening cross section is controllable via a control body 26 in the
form of a flap, which may be placed on the valve seat 24 to close
the opening cross section and which may be lifted off the valve
seat 24 to open the flow cross section of the bypass channel
22.
[0034] The control body 26 is fastened to a lever 28 that extends
from a flap shaft 30 and is integrally formed therewith for this
purpose. The flap shaft 30 has the same axis of rotation as the
output shaft/drive shaft 32 of an actuator 34 via which the control
body 26 is operated. The output shaft 32 thereby extends out of an
actuator housing 36 towards the turbine housing 18 and is connected
for rotation with the flap shaft 30 by an Oldham coupling 38, with
other couplings also being conceivable.
[0035] As can in particular be seen in FIG. 3, a bearing 40
supports the output shaft 32 in the actuator housing 36 which is
formed as an integral die-cast part. An output gear 42 of a
transmission 44, designed as a gear segment, is arranged on the
output shaft 32, the transmission 44 being arranged inside the
actuator housing 36 and being configured, according to the present
invention, as a worm wheel gear unit. The worm wheel gear unit
consists of a helical gear 46 serving as a drive gear which meshes
with the larger gear of a double gear 48, whose smaller gear meshes
with the output gear 42. The double gear 48 is supported on an axle
50 fastened in the actuator housing 36.
[0036] The helical gear 46 is arranged on an input shaft 52 of an
electric motor 54 which serves as a drive. The electric motor 54 is
arranged in a receiving space 56 of the actuator housing 36, the
receiving space 56 extending vertically with respect to the output
shaft 32.
[0037] A return spring 58 is additionally arranged in the actuator
housing 36, which return spring 58 surrounds the output shaft 32
and a first end leg 60 of which rests on an abutment in the
actuator housing 36, while the second end leg 62 engages into the
output gear 42 so that, in the event of a failure of the electric
motor 54 or other malfunction, the output shaft 32, and thus the
control body 26, is rotated into a fail-safe position so as to
avoid damage to the turbocharger 10 caused by exceeding the maximum
permitted rotational speed.
[0038] A coolant inlet port 64 and a coolant outlet port 66 are
formed on the actuator housing 36 at the receiving space 56 of the
electric motor 54, which are connected with a coolant channel 68
formed in the actuator housing 36. As can be seen in FIG. 2, this
coolant channel 68 is formed by a first coolant channel section 70
surrounding transmission 44, as well as by a second coolant channel
section 72 which extends all over the circumference of the electric
motor 54, except for a partition wall 74 formed in the axial
direction with respect to the input shaft 52 between the coolant
inlet port 64 and the coolant outlet port 66. The partition wall 74
extends over the entire axial height of the electric motor 54 so
that the coolant is forced to flow into the first coolant channel
section 70 via a passage opening 76. Another partition wall is
formed (not visible in the drawings) in the second coolant channel
section 72 which extends over the axial height parallel to the
output shaft 32 of the second coolant channel section. This
partition wall is situated in the region of the actuator housing 36
surrounding the transmission 44, which region adjoins the receiving
space 56 of the electric motor 54, whereby the coolant is forced to
flow around the transmission 44. After having flowed around the
transmission 44, the coolant again flows through a second passage
opening (not visible in the drawings) into the second coolant
channel section 72 that surrounds the electric motor 54, but on the
other side of the partition wall 74, in the direction of the
coolant outlet port 66.
[0039] The first coolant channel section 70 and the interior of the
actuator housing 36 is closed by an actuator cover 78. This
actuator cover 78 is in particular manufactured by a plastics
injection molding. For a tight closure of the coolant channel 68, a
circumferential projection 80 is formed on the actuator cover 78 on
the side facing the actuator housing 36, the projection 80
corresponding to the shape of the first coolant channel section 70
and having the width thereof so that the projection 80 protrudes
into the recess in the actuator housing 36 serving as the first
coolant channel section 70. On its opposite sides, seen in cross
section, a respective seal 82 is formed extending circumferentially
with the projection, the seal 82 providing a tight closure of the
first coolant channel section 70.
[0040] Besides its function as a closure for the actuator housing
36, the actuator cover 78, which is fastened to the actuator
housing 36 by screws 83, also serves as a carrier for electric
components of the actuator 34. The side of the actuator cover 78
directed towards the interior of the actuator 34 is accordingly
provided with a Hall sensor 84 for position feedback, the sensor
communicating with a magnet 86 arranged on the end of the output
shaft 32. A circuit board 87, which may include control elements of
the actuator 34 and on which the Hall sensor 84 is arranged, is
further formed on this side of the actuator cover 78. The circuit
board 87 and the Hall sensor 84 are connected with a connector 88
via invisible lines molded in the actuator cover 78, the connector
being made integrally with the actuator cover 78 and extending
outward. Two projections 90 extend towards the electric motor 54 on
the side of the actuator cover 78 opposite the connector 88 in
which terminals are formed via which the contact tabs 92 of the
electric motor 54 are connected for power supply to the electric
motor 54.
[0041] As can be seen in FIG. 2, the electric motor 54 is pushed
vertically with respect to the axis of the output shaft 32 from
outside into the receiving space 56 against an abutment of the
actuator housing 36. This abutment has an opening for receiving the
A-bearing 94 of the electric motor 54 through which the helical
gear 46 protrudes into the portion of the actuator housing 36
surrounded by the first coolant channel section 70. Two openings
are further formed in the region of the abutment through which the
contact tabs 92 of the electric motor 54 extend into the two
projections 90 of the actuator cover 78.
[0042] On the side axially opposite the actuator cover 78, the
receiving space 56 of the electric motor 54 is closed with a motor
cover 96 that simultaneously closes the second coolant channel
section 72. This motor cover 96 has a recess 98 for receiving a
B-bearing 100 of the electric motor 54 as well as an invisible
axial groove into which a corrugated spring 102 is placed to clamp
the electric motor 54 in the axial direction. Similar to the
actuator cover 78, the motor cover 96 is further formed with a
circumferential projection 104 with, seen in cross section,
opposite ring seals, the projection 104 extending into the cooling
channel section 72 and sealing the cooling channel section 72 to
the outside. The motor cover 96 is fastened by a clamping ring 106
which, in the assembled state, is retained in a radial groove 108
at the axial end of the receiving space 56 of the actuating housing
36.
[0043] The actuator 34 is fastened to the turbine housing 18 by
screws 110 inserted through eyelets 112 formed at the sides of the
actuator housing 36 and threaded into domes 114 with female threads
formed on the turbine housing 18. A heat dissipation sheet 116 is
provided between the actuator 34 and the turbine housing 18 for an
additional shielding of the actuator housing 36 from heat
radiation.
[0044] The described waste gate valve requires little installation
space, in particular in the axial direction. It also has its own
cooling circuit that makes it possible to control the temperature
in the housing of the waste gate valve separately, i.e.,
independent of the turbine housing of the turbocharger. The
actuator of the waste gate valve may be preassembled and thereafter
be mounted on the turbine housing so that a direct connection of
the actuator to the valve is obtained, whereby a precise control
becomes possible. A long service life is achieved due to the good
thermal decoupling of the actuator from the turbine housing and, as
a consequence thereof, the low thermal load on the electric motor
and on the other electronic components. Assembly is greatly
simplified since all electronic components are formed on the
actuator cover and are thus mounted together with the actuator
cover which at the same time closes the coolant channel. The number
of components that are present and which must be mounted is thereby
reduced.
[0045] It should be clear that the present invention is not
restricted to the shown embodiment, but that various modifications
are possible which fall within the scope of protection of the main
claim. It is in particular possible to fasten the covers in a
different manner or to use axial seals. It is also conceivable to
use a continuous shaft with poor thermal conductivity. Reference
should also be had to the appended claims.
* * * * *